Further miniaturization of electric devices has been desired, in accordance with the requirements of making the devices be smaller in size and higher in density. Thus, the researches of a nanostructure have attained remarkable progress which is represented by new functional organic molecules and nanoparticles. Utilization of characteristics of a nanostructure in electric devices is considered to be effective for miniaturization of electric devices, and research institutes, companies, and the like intensively study the utilization. For example, there is a device attracting attentions that is composed of two electrodes spaced from each other by a minute gap (hereinafter, such a pair of electrodes is referred to as “nanogap electrodes”) and, over the gap, a functional organic molecule is bridged. For example, the device described in Science, 289, pp. 1172-1175 (2000) is formed by arranging a catenane-based molecule in the gap of nanogap electrodes made of platinum. The above-described Science, 289, pp. 1172-1175 (2000) describes a technique in which a voltage is applied to the electrodes to subject the catenane-based molecule to an oxidation-reduction reaction, thereby the device can carry out a switching operation.
Further, a device having nanogap electrodes bridging over its gap with nanoparticles also attracts attentions. One of the examples is the device described in Nature, 433 pp. 47-50 (2005) that is formed by preparing nanogap electrodes using silver sulfide and platinum, and arranging silver particles in its gap. The above-described Nature, 433 pp. 47-50 (2005) describes a technique in which a voltage is applied to the electrodes to cause an electrochemical reaction, thereby bridging/breaking between the electrodes can be performed by use of stretching/shrinking of silver particles, that is, a switching operation can be performed.
Furthermore, in any of the conventional switching devices exemplified herein, it is difficult to make the distance of the gap between the nanogap electrodes sufficiently small. With respect to this-point, there is a technique of the method of producing nanogap electrodes having a small distance of the gap between the nanogap electrodes, for example, which is disclosed in JP-A-2005-79335 (“JP-A” means, unexamined published Japanese patent application).